The field of this invention relates generally to vacuum valve systems, and more particularly to vacuum valve systems used between a vacuum source and a respirator breathing jacket to help control breathing by a human user.
Vacuum valve systems are now in use for operating breathing jackets. An example of a vacuum valve breathing system is the Emerson Chest Respirator consisting of a model 33-CRS chest respirator pump with hose, a body wrap, a support grid, and a backplate, manufactured by the J. H. Emerson Company of Cambridge, Mass. Another example of a commercially available system is the Monaghan 170 C Respirator which also includes a shell for wrapping around a human user, manufactured by Monaghan, A Division of Sandoz, Inc.
Both of these systems are similar in construction and operation. An airtight jacket encloses, in spaced apart relation, at least a part of the torso of the user. The jacket is coupled through a hose to a pump which is controllable through dials and switches by the user or an operator. With these controls, the operator can (1) vary the frequency of inspiration and expiration, that is, the breathing rate or how fast the user breathes, and (2) vary the duration of each inspiration and expiration, that is, determine how deep or shallow each breath will be.
Expensive and technically complex control systems are now in use to control frequency and duration of breathing, but even with such sophisticated controls, multiple adjustments are necessary to finally obtain an optimum mix of breathing frequency and duration. Such control systems and the apparatus which they control are constructed so that adjustment of either the frequency or the duration of breathing affects the other. Thus, frequency variations produce duration variations, and adjustments to the duration produce changes in the breathing frequency. Reaching the optimum frequency and duration, therefore, often requires multiple adjustments by even highly skilled personnel.